The invention is based on a diagnostic tester for motor vehicles having programmable control units.
Diagnostic testers for motor vehicles that contain programmable control units are generally known. Such programmable control units can contain self-diagnostic means and control, monitor the engine control and other systems of the motor vehicle in program-controlled fashion. In self-diagnosis, error codes are generated and stored. These control units and the error code storage devices can be connected to an external diagnostic tester via a diagnostic/test plug in the motor vehicle.
The interaction between motor vehicle control units having self-diagnostics and the external diagnostic tester are described in detail in an article, for example, by D. Nemec entitled xe2x80x9cMxc3x6glichkeiten komfortabler Testgerxc3xa4te zur Auswertung der Eigendiagnose von Steuergerxc3xa4ten im Kraftfahrzeugxe2x80x9d [xe2x80x9cPossibilities of convenient test units for the evaluation of self-diagnosis of control units in the motor vehiclexe2x80x9d] in VDI Berichte [xe2x80x9cVDI Reportsxe2x80x9d] No. 687, 1988, pages 365-385. Among other things, this article also discusses, on page 384, for example, that, with variant programming, entire control unit programs can be loaded into the unprogrammed control unit via the interface of the diagnostic/test plug. This is essential in particular before the start of a series, because the manufacturer can still change parameters at that point. Moreover, spare-parts stocking is reportedly easier, because it is sufficient to stock unprogrammed control units which can then be programmed and installed from case to case.
The system scope of engine controls provided for in motor vehicles has become very comprehensive due to the requirements for convenience, security, and diagnostics. For example, a Motronic engine control system has approximately 4,000 data that must be adapted to the requirements of the respective motor vehicle. Due to the generally tight time frame for the start of a series of engine controls, data or program changes cannot be ruled out during the current series. Today, engine controls having self-diagnostics are predominantly equipped with programmable flash storage devices. In order to reprogram to correct data or functions, the control units must be replaced or connected to programming units. If there are errors in the serial programs, high costs are incurred despite the ability to reprogram due to additional expense for the programming.
Object of the present invention is to indicate a possibility according to which the respective current version is cost-effectively programmed in the control units in simple fashion.
In contrast to the prior art, the diagnostic device according to the invention has the advantage that, during regular maintenance of the motor vehicle in the workshop, when the external diagnostic tester available in the workshop is connected, the programs available in the control units are automatically checked to determine which version they contain and that, if necessary, a reprogramming of the programs available in the control units is carried out by the external diagnostic tester equipped accordingly, so that the most current version is always available there. No additional work expenditure is created for the service personnel by the automatic procedure of checking and if necessary, programming. During maintenance work, e.g., during an oil change, the diagnostic tester is left connected until the current program record has been programmed. No additional costs are generated for the control units themselves, because an interface for reprogramming or programming is already available there. The customer therefore receives the respective current program status as part of maintenance work on the vehicle. Warranty costs for reprogrammings in the field can therefore be prevented as well. Moreover, It can be taken into account by means of the reprogramming in simple fashion that error-free programs are not always available in the condition at delivery as the complexity of systems increases.
According to the invention, this is achieved in principle by the fact that the external diagnostic tester is equipped with a program recognition and program loading device, and the program version contained in the connected control unit is queried and recognized using the program recognition device, and that then, if the program available in the motor vehicle and recognized via the diagnostic/test plug, available in the connected control unit of the motor vehicle is not stored there in the latest and most current version, the respective most current version is loaded by the program loading device of the diagnostic tester into the program storage device of the pertinent control unit of the motor vehicle.
According to an advantageous and suitable further development of the device according to the invention, in addition to the program for the motor vehicle control units having self-diagnostic means, in particular the program for engine control, programs of control units of other systems and subsystems provided for in the motor vehicle are also checked and, if necessary, newly loaded or reprogrammed. This provides a very flexible possibility for keeping the various control and diagnostic programs available in the various control units of a motor vehicle updated to the respective most current status.
In very suitable and advantageous embodiment and further development of the diagnostic tester according to the invention, the program version check and, if necessary, the required reprogramming, is carried out automatically by the external diagnostic tester. As a result, no particular attention is required by the maintenance and service personnel to carry out this point during maintenance and service work.
According to an advantageous embodiment of the device according to the invention, the external diagnostic tester is equipped with the respective latest versions of the necessary programs. Under certain circumstances, this can lead to too great of a demand on the storage device of the diagnostic tester.
According to a further very advantageous embodiment of the invention, it is therefore provided for that the external diagnostic tester automatically establishes communication with a central data base in order to check the program version and, if necessary, to obtain the current program version that applies for the control unit connected to the diagnostic tester and to store it there.
In a further advantageous embodiment of this version of the diagnostic tester according to the invention, the communication between the diagnostic tester and the central data base takes place-via dedicated line, or wirelessly via mobile telecommunication from the workshop or the motor vehicle itself.
In a further advantageous embodiment of the diagnostic tester according to the invention, it is provided for, in order to increase security, that the external diagnostic tester is equipped with a special authorization to check the program version currently available in the connected control unit of the motor vehicle and, if necessary, to reprogram the corresponding program.
The invention will now be explained in greater detail using an embodiment.